Ok this is the best thing to do:
1) Bring only a spade, sextant, chart, watch, your clue, either bow and arrows -or- runes to cast magic, and a Dragon Dagger (if you dont have a dragon dagger, bring some other dagger or a scimmy-- anything with a slash attack)
2) It would be best to have 43 prayer, fully charged. Not usually needed though.
3) Since it's just north of the lever, no need to bank, just run for it.
4) You'll fight a Zamorak Wizard. From my point of view it's very easy.
You can try to find a safe spot to range/mage it. It does cast magic attacks, so put on Protect From Magic.
5) After you kill it, go back to the spot and dig again.
6) Run south and pull the lever back to Ardougne BEFORE opening the casket.
--If you get attacked put on the appropriate prayer--
(Protect from Magic, Range, Melee, etc.)
Hope this helps
